海绵措施下降雨径流模拟及污染物削减率评价

Rainfall runoff simulation and pollutant reduction rate evaluation under sponge measures

【目的】为探明海绵措施对降雨径流的削减效果和污染物削减能力,以固原市23 km2海绵试点区为研究对象,模拟不同重现期下海绵措施实施前后降雨径流及污染物的变化规律。【方法】采用高精度地形、GPU加速技术,构建适用于固原市洪涝模拟的水文水动力模型。【结果】结果表明:(1)不同降雨情景下,实施海绵措施后,年径流控制率提高16%~20%,污染物削减率均在98%左右。(2)降雨雨型对径流总量控制率影响明显,小雨量时,大部分降雨被留在当地。(3)模型模拟结果为海绵措施布置提供了指导依据,2号积水点建议布设路旁植草沟和渗井,以减少主干道往该处汇流的水量;3号积水点建议完善排水管网;6号积水点建议布设植草沟及滞留溏;10号积水点建议在西侧主干道布设生态植草沟、透水性路面。【结论】构建了适用于固原市的洪涝模型,可实现海绵措施布置对降雨径流和污染物削减率的模拟,为该城市雨洪管理和城市规划提供了科学依据。

[Objective]In order to explore the effect of sponge measures on rainfall runoff reduction and pollutant reduction capacity,the 23 km2 sponge pilot area in Guyuan City was taken as the research object to simulate the variation of rainfall runoff and pollutants before and after the implementation of sponge measures under different return periods.[Methods]Using high-precision terrain and GPU acceleration technology,a hydrological and hydrodynamic model suitable for flood simulation in Guyuan City was constructed.[Results]The result showed that:(1)Under different rainfall scenarios,after the implementation of sponge measures,the annual runoff control rate increased by 16%~20%,and the pollutant reduction rate was about 98%.(2)Rainfall pattern has a significant effect on the total runoff control rate. When the rainfall is small, most of the rainfall is left in the local area. (3) The simulation result of the model provide guidance for the arrangement of sponge measures. It is suggested to set up grassed ditches and seepage wells beside the road in No. 2 water accumulation point, so as to reduce the amount of water flow from the main road to this place. No. 3 water accumulation point is recommended to improve the drainage pipe network;No. 6 water accu-mulation point is recommended to set up grass planting ditch and retention pond;No. 10 water accumulation point is recommen-ded to set up ecological grass planting ditch and permeable pavement on the main road on the west side. [Conclusion]A flood model suitable for Guyuan City is constructed, which can realize the simulation of rainfall runoff and pollutant reduction rate by sponge measures arrangement, and provide a scientific basis for urban stormwater management and urban planning.